Enzyme substrate method is widely used for coliform bacteria monitoring in medical wastewater. Coliform bacteria serves as a key monitoring parameter for medical wastewater. There are multiple available testing methods, and users can select suitable testing solutions based on their actual working conditions. Common detection approaches include membrane filtration method, multiple-tube fermentation method and enzyme substrate method. This article introduces the application of the enzyme substrate method to test coliform bacteria concentration in medical wastewater.
As a standard testing method for coliform bacteria in water samples, the enzyme substrate method works by incubating samples under controlled conditions for a set duration. Coliform bacteria produce β-galactosidase, which breaks down the colorless substrate o-nitrophenyl-β-D-galactopyranoside (ONPG) in selective culture medium into o-nitrophenol (ONP), generating a yellow color reaction. Coliform bacteria can also produce β-glucuronidase. This enzyme decomposes 4-methylumbelliferyl-β-D-glucuronide (MUG) in selective medium into 4-methylumbelliferone.
Count the number of positive reactions, refer to the MPN table and divide the value by the dilution factor of the inoculated sample to calculate the coliform bacteria concentration in the water sample. The test follows the specification of HJ 1001-2018 for the determination of coliform bacteria in water quality.
The WECT-900 Coliform Online Analyzer adopts the enzyme substrate method. Equipped with a coliform detection system based on biosensing technology, the instrument supports water contamination monitoring. It evaluates coliform levels in water samples by measuring light intensity changes of the solution and making comparisons with non-toxic blank control samples.
This analyzer is applied to medical wastewater monitoring, drinking water source safety inspection and emergency assessment. It supports early warning of water pollution risks, and assists in risk alerts for common food and waterborne contamination incidents.
